急性单核细胞白血病M5a和M5b细胞遗传学与临床表现的比较.docx

急性单核细胞白血病M5a和M5b细胞遗传学与临床表现的比较.docx

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急性单核细胞白血病M5a和M5b细胞遗传学与临床表现的比较

急性单核细胞白血病M5a和M5b细胞遗传学与临床表现的比较

【摘要】　　为了比较急性单核细胞白血病M5a和M5b细胞遗传学差异，并研究其与临床行为之间的相互关系，采用骨髓直接法和24小时短期培养法制备染色体标本，用G显带技术对58例成人初发急性单核白血病细胞进行核型分析，同时对其临床资料进行回顾性研究。

结果表明：

58例患者中正常核型28例，异常核型30例，其中正常核型在M5b中出现率高于M5a（P＝0.0001），异常核型中11q23异常和＋8染色体在M5a中均较M5b常见（P<0.01）；临床上异常核型的M5患者常有高白细胞（WBC）计数，中枢神经系统浸润，完全缓解（CR）率低及存活期明显缩短的特征。

结论：

急性单核细胞白血病在遗传和临床上是一组异质性疾病，但M5a和M5b似乎具有各自独特的遗传学背景和临床表现。

【关键词】急性单核细胞白血病；AML-M5a；AML-M5b；细胞遗传学

　　ComparisonofCytogeneticsandClinicalManifestationsbetweenM5aandM5bofAcuteMonocyticLeukemia

　　AbstractTocomparethecytogeneticdifferencebetweenM5aandM5bofacutemonocyticleukemiaandtostudythecorrelationbetweenkaryotypesandclinicalmanifestations，atotalof58casesofdenovoadultAMLM5havebeeninvestigated.Chromosomemetaphasesofbonemarrowcellswerepreparedbyusingdirectmethodand24hoursshort-termculture.ThekaryotypeswereanalyzedbyG-banding.Meanwhile，clinicalinformationofthesecaseswerestudiedretrospectively.Theresultsshowedthattherewere28withnormalkaryotypeand30withaberrantkaryotypein58cases.ThefrequencyofnormalkaryotypeinpatientswithM5bwassignificantlyhigherthanthatinpatientswithM5a（P=0.0001）.The11q23aberrationsandtrisomy8weremorecommoninpatientswithM5aincomparisonwithpatientswithM5b（P<0.01）.ThepatientswithAMLM5withaberrantkaryotypehadahigherincidenceofhyperleucocytosis，extramedullarycentralnervesysteminfiltration，lowercompleteremission（CR）rateandshorteroverallsurvival.Itisconcludedthatacutemonocyticleukemiaisaseriesofheterogeneousdiseases，adistinctivecytogeneticfeaturescanbeobservedbetweenpatientswithAMLM5aandM5b，theseresultswillprovideinsightsintotheclassificationandpathogenesismechanismofAMLM5atmolecularlevel.

　　Keywordsacutemonocyticleukemia;AML-M5a;AML-M5b;cytogenetics

Acutemyeloidleukemia（AML）canbeclassifiedbyFABsystemintodifferentgroupsbasedoncellularmorphologyandcytochemistrystainingofbonemarrowcells.Accordingtothedifferentiationstageofmonocyticcells，acutemonocyticleukemia（AML-M5）consistsoftwogroups:

M5a，thepercentageofmonoblastsis≥80%;M5b，themajorityofmonocyticcellsarepromonocytes（blasts＜80%）［1］.Inaddition，hematologicalmalignanciescanbeclassifiedaslymphocytic，myeloid，histocyticandmastocyticseriesbasedontheoriginofmalignantcellsbytheWHO.Eachgroupisdeterminedbymorphology，cytogeneticsandclinicalcharacteristics.However，thesetwoclassificationsystemscannotbeusedtodifferentiatethecytogeneticcharacteristicsandclinicalmanifestationsbetweenpatientswithM5aandM5b.Inthepresentstudy，weinvestigated58newlydiagnosedAMLM5patientsinordertobettercharacterizethecytogeneticchangesandclinicalmanifestationsofthesepatientsformoreaccurateclassificationandunderstandingofthepathogene-sisofthedisease，whichcouldleadtothedevelopmentofanoveltherapeuticstrategy.

　　MaterialsandMethods

　　Patients

　　DuringtheperiodfromJanuary2000toJune2004，58patientswerenewlydiagnosedwithAMLM5inthedepartmentofHematologyofUnionHospitalaffiliatedtoTongjiMedicalCollege，HuazhongUniversityofScienceandTechnology（Wuhan）.Theclinicalrecordsandlaboratorytestreportsofthesecaseswerereviewed.Theclinicaldiagnosiswasmadebasedontheclinicalsymptoms，peripheralbloodcounts，bonemarrowexamination.26outofthe58patientswereclassifiedasM5aand32asM5b.Therewere12malesand14femalesofAMLM5apatients，agedfrom18to59withamedianageof39.5，while20malesand12femalesofAMLM5bpatientsagedbetween28to66withamedianageof48.

　　Cytogeneticanalysis

　　2-3mlsofheparinizedbonemarrowfrompatientswereculturedinRPMI1640supplementedwith20%fetalcalfserumand20U/mlheparin.Thecelldensitywasadjustedto1×106/ml.Thesampleswereincubatedat37℃for24hours，thentreatedbycolchicineswiththefinalconcentrationof0.05μg/mlforanother42minutes.Standardcytogeneticpreparationwasmade;amodifiedchromosomebandingtechnique（G-banding）wasused.Forchromosomeanalysisatleast30-50metaphasechromosomesshouldbecountedineachsample，and10metaphasechromosomeswereanalyzedbymicroscopyormicrophotography.KaryotypeswereanalyzedaccordingtotheInternationalSystemforCytogeneticNomenclature（ISCN.1995）.

　　Protocols

　　Allpatientsweretreatedwithregimensasfollows:

（1）DA（daunorubicin45mg/m2perdaybyintravenousinfusion（iv），day1to3，pluscytarabine100-200mg/m2perdaybyintramuscularinjection（im）day1to7）;

（2）HA（homoharringtonine2-3mg/m2byivperday，day1to3，pluscytarabine100-200mg/m2perdaybyim，day1to7）;（3）IA（idarubicin10mg/m2perdaybyiv，day1to3，pluscytarabine100-200mg/m2perdaybyimday1to7）;（4）MEA（mitoxantrone8-12mg/m2perday，day1to3，plusetoposide100mg/m2perdaybyivdrip，day4to5，pluscytarabine100-200mg/m2perdaybyim，day1to5）.Subsequently，somepatientsreceivedstrengtheningchemotherapywithcytarabine1.5g/m2twiceadayfor6days，whilepatientsolderthan70yearsreceivedthesametherapyforonly3days.Outofthe58patients，twounderwenthumanleukocyteantigen-matchedallogeneicbonemarrowtransplantationandoneunderwentperipheralbloodstemcelltransplantationafterthediseaseswentintocompleteremission.

　　Definitionofresponse

　　Completeremissionwasdefinedineachprotocolasabsenceofleukemiainthebonemarrowindicatedbylessthan5%blasts，recoveryofnormalperipheralbloodcellcountsasindicatedbyabsoluteneutrophilcount≥1.5×109/L，andplateletcount≥100×109/L，andabsenceofextramedullaryleukemia.

　　Statisticalanalysis

　　ClinicalandcytogeneticcharacteristicsofAMLM5apatientswerecomparedwiththatofAMLM5bpatientsusingχ2test.

　　Results

　　Cytogeneticanalysis

　　Outof58patients，28（48.3%）hadnormalkaryotypes，thefrequencyofwhichwassignificantlyhigherinthepatientswithAMLM5b（85.7%，n=24）thanthatinthepatientswithAMLM5a（14.3%，n=4）（P<0.01）;30（51.7%）hadaberrantkaryotypesbeinginvolvedin11q23/MLL（AMLM5avsAMLM5b:

833%vs16.7%，P<0.01），soletrisomy8（AMLM5avsAMLM5b:

88.9%vs11.1%，P<0.01），trisomy8plus11q23/MLL（AMLM5avsAMLM5b:

333%vs66.7%）andotherchromosomeabnormalities，outofwhichtrisomy21intwopatients，5q-inone，7q-inone，t（9;22）inone，andt（8;16）inanotherone.TheresultsofcytogeneticanalysisforallAMLM5patientsaresummarizedinTable1.　　Clinicalcharacteristics

　　Outofallthepatients，abnormallyhighwhitebloodcellcounts（≥50×109/L）weredetectedin27patients（M5avsM5b∶14vs13）;hepatosplenomegalywasobservedin22patients（M5avsM5b∶11vs11）;extramedullarydiseaseintheskinwasfoundin16patients（M5avsM5b∶9vs7），enlargementoflymphnodesin20patients.15patientshadcentralnervoussystemleukemia（M5avsM5b∶9vs6）;14patientshadthedisseminatedintravascularcoagulation（M5avsM5b∶8vs6）.

Thecompleteremissionratewas42.3%（n=11）forpatientswithM5a，56.3%（n=18）forpatientswithM5b，and50%（n=29）forallAMLM5patients.Thepercentageoftheone-yeardisease-freesurvival（DFS）inpatientswithAMLM5awas26.9%（n=7），whileitwas34.4%（n=11）inpatientswithAMLM5b.Theclinicalcharacteristicsbetweenthetwosubtypeswerenotsignificantlydifferent（P＞0.05）.TheseresultsarelistedinTable2.Table1.CytogeneticdataforpatientswithAMLM5subtypes（略）Table2.ClinicalcharacteristicsofAMLM5patientswithvariouskaryotypes（略）

　　Discussion

　　Specificnon-randomchromosomalabnormalitiesareoftenobservedincertainsubtypesofhematologicmalignancy.MoreaberrantcytogeneticshasbeendiscoveredinpatientswithAMLM5afterinitiallyfindingoft（9；11）（p21；q23）inM5apatientbyBerger［2］in1980.Haferlachetal［3］consideredthat11q23aberrationandtrisomy8weresignificantlyassociatedwithAML-M5.Tkachuketal［4］foundthat11q23abnormalitiesareinvolvedintheMLLgene（ornamed“ALL1”or“HRX”），spanning90kbofcDNAandencodinga3968-aminoacidproteinwithmolecularmassabout430kD.Thewild-typeMLLproteinhasthreeAT-hookDNAbindingdomainsandmultiplezincfingerdomains.MLLgene-encodedproductasatranscriptionfactorthenmaybindwiththegenesregulatingbodydevelopmentandcelldifferentiation［5］.ThegenerearrangementsofMLLsuchas11q23translocationalteritsstructureandfunctionandmayleadtoleukemogenesis.

　　Meanwhile，thetrisomy8isachromosomeabnormality.Althoughtheinducingmechanismandthebiologicroleofthetrisomy8areunknown，therelationshipbetweenthetrisomy8andmonocyticmalignancyhasbeensuggested［6］.Theoccurrenceoftrisomy8mayenhancetheexpressionofgenes，leadingtothedevelopmentofleukemias.Inthisstudy，theincidenceof“normalkaryotypes”washigherinpatientswithM5bthanthatinpatientswithM5a（P<0.001）;theinvolvementof11q23aberrantionsandtrisomy8weredetectedmorefrequentlyinpatientswithM5athanthatwithM5b（P<0.01）inaccordancewithpriorstudies［3，6］.TheseresultsindicatethatthegenomicinstabilityismorecommonandcomplexinM5apatientleukemiccellsthanthatinM5bcells.

TheclinicalcharacteristicsofpatientswithAMLM5includedextramedullaryinfiltrationwithhighWBCcounts，lowcompleteremissionrateandshortdisease-freesurvival（DFS）.Inourstudy，nosignificantdifferencewasfoundregardingthosecharacteristicsbetweenthetwosubtypes，inagreementwiththeresultsfromthestudyoftheEasternCooperativeOncologyGroup（ECOG）on81patientswithAMLM5［1］.

　　Meantime，Schochetal［7］analyzed1897AMLcaseswith11q23abnormalities，an